SceneCacheFileFormat: Handle invalid file path.

Handle the exception to avoid crashing the application.

Author: lucienfostier

contrib/IECoreUSD/src/IECoreUSD/SceneCacheFileFormat.cpp

@@ -175,6 +175,11 @@ bool UsdSceneCacheFileFormat::WriteToFile( const SdfLayer& layer, const std::str
 	SceneInterfacePtr outScene;
 
 	outScene = SdfFileFormatSharedSceneWriters::get( filePath );
+	if ( !outScene )
+	{
+		IECore::msg( IECore::Msg::Error, "UsdSceneCacheFileFormat::WriteToFile", boost::format( "Invalid file path \"%s\" for layer \"%s\"." ) % filePath % layer.GetIdentifier() );
+		return false;
+	}
 
 	SceneInterface::NameList childNames;
 	usdScene->childNames( childNames );

contrib/IECoreUSD/src/IECoreUSD/SdfFileFormatSharedSceneWriters.cpp

@@ -35,6 +35,7 @@
 #include "SdfFileFormatSharedSceneWriters.h"
 
 #include "IECore/LRUCache.h"
+#include "IECore/MessageHandler.h"
 
 using namespace IECore;
 using namespace IECoreScene;
@@ -61,7 +62,15 @@ class Cache : public SceneLRUCache
 
 		static SceneInterfacePtr fileCacheGetter( const std::string &fileName, size_t &cost )
 		{
-			SceneInterfacePtr result = SceneInterface::create( fileName, IECore::IndexedIO::Write );
+			SceneInterfacePtr result = nullptr;
+			try
+			{
+				result = SceneInterface::create( fileName, IECore::IndexedIO::Write );
+			}
+			catch ( ... )
+			{
+				IECore::msg( IECore::Msg::Error, "SdfFileFormatSharedSceneWriters::SceneLRUCache", boost::format( "Unable to open file path \"%s\" for writing IndexedIo data." ) % fileName );
+			}
 			cost = 1;
 			return result;
 		}